Compositions and techniques for forming organic thin films

ABSTRACT

The present teachings relate to various embodiments of a curable ink composition, which once printed and cured form polymeric films on a substrate such as, but not limited by, an OLED device substrate. Various embodiments of the curable ink compositions comprise di(meth)acrylate monomers, as well as multifunctional crosslinking agents and curing kinetics control additives.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. provisional patentapplication No. 62/647,470 that was filed on Mar. 23, 2018 and to U.S.provisional patent application No. 62/659,493 that was filed on Apr. 18,2018, the entire contents of which are incorporated herein by reference.

OVERVIEW

Interest in the potential of organic light-emitting diode (OLED)optoelectronic device technology, such as OLED display and OLED lightingdevices, has been driven by OLED technology attributes that includedemonstration of devices that have highly saturated colors and providehigh-contrast, and are ultrathin, fast-responding, and energy efficient.

Various OLED optoelectronic devices are fabricated from inorganic andorganic materials, including various organic thin film emissivematerials. Such materials can be susceptible to degradation by water,oxygen and other chemical species in the environment. To address this,OLED devices have been encapsulated in order to provide protectionagainst degradation. For example, encapsulation stacks that includealternating inorganic barrier layers and organic planarizing layers havebeen used to isolate the moisture- and/or oxygen-sensitive materials inOLEDs.

Though various manufacturing methods can be used for the deposition ofthe planarizing layer in an encapsulation stack, inkjet printing canprovide several advantages. First, a range of vacuum processingoperations can be eliminated because inkjet-based fabrication can beperformed at atmospheric pressure. Additionally, during an inkjetprinting process, an organic planarizing layer can be localized to coverportions of an OLED substrate over and proximal to an active region, toeffectively encase an active region, including lateral edges of theactive region. The targeted patterning using inkjet printing results ineliminating material waste, as well as eliminating the need for masksand therefore challenges presented with the alignment and foulingthereof, as well as eliminating additional processing typically requiredto achieve patterning of an organic layer when utilizing, for example,various vapor deposition processes.

Accordingly, various compositions of the present teachings can bedeposited on a substrate and cured to form an organic layer on asubstrate. In various methods of the present teachings, inkjetdeposition can be used for the deposition of an organic thin filmcomposition on a substrate, followed by a curing process to form anorganic layer on a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the features and advantages of the presentdisclosure will be obtained by reference to the accompanying drawings,which are intended to illustrate, not limit, the present teachings.

FIG. 1 is a schematic section view of an optoelectronic device,illustrating various aspects of a fabrication.

FIG. 2 is a graph of viscosity versus temperature for variousembodiments of a first organic monomer composition of the presentteachings.

FIG. 3 is a graph of viscosity as a function of temperature for variousembodiments of a second organic monomer composition of the presentteachings.

FIG. 4 is a graph of transmission as a function of wavelength for thinfilms formed from an exemplary composition of the present teachings incomparison to the transmission of a glass reference material.

FIG. 5 illustrates generally examples of a gas enclosure system forintegrating and controlling gas sources such as can be used to establisha controlled process environment, as well as providing a pressurized gasand at least partial vacuum for use with a floatation table.

FIG. 6 illustrates generally an isometric view of at least a portion ofa system, such as including an enclosed printing system and an enclosedcuring system.

FIG. 7 is a flow diagram that illustrates generally a process for thefabrication of an organic thin films on various device substrates.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present teachings relate to various embodiments of curable inkcompositions, which once deposited and cured, provide a polymeric filmover at least a portion of a substrate in an electronic device.

Electronic devices on which the polymeric films may be formed includeelectronic devices having one or more components that are moisture-and/or oxygen-sensitive—that is, one or more components whoseperformance is negatively affected by reactions with water and/or oxygenin the atmosphere. In such devices, the polymeric film may be includedas a planarizing layer in a multi-layered encapsulation stack, asdescribed in greater detail below. The polymeric films may also be usedto improve light extraction for a light-emitting optoelectronic device,to provide thermal dissipation for a heat-generating device, and/or toprovide protection from mechanical damage for an electronic device thatis susceptible to breaking, including electronic devices that have glasscomponents, such as glass screens. Electronic devices over which thepolymeric films can be formed include optoelectronic devices, such asOLEDs, as well as lithium batteries, capacitors, and touch screendevices. Because the polymeric films are flexible, they are suited foruse with flexible electronic devices.

In some embodiments of the encapsulated devices, the polymeric films aredisposed over a light-emitting active region of an OLED devicesubstrate. The light-emitting active region of an OLED device caninclude various materials that degrade in the presence of exposure tovarious reactive species, such as, but not limited by, water vapor,oxygen, and various solvent vapors from device processing. Suchdegradation can impact the stability and reliability of an OLED device.In order to prevent such degradation, a multilayered encapsulation stackcan be used to protect the OLED, wherein the encapsulation stackincludes a film of an inorganic barrier layer adjacent to a polymericplanarizing layer. An encapsulation stack will include at least one suchinorganic barrier layer/polymeric planarizing layer pair (“dyad”), butcan include multiple stacked dyads. Moreover, the lowermost layer in theencapsulation stack, which is in contact with at least one substrate ofthe electronic device, can be either an inorganic barrier layer or apolymeric planarizing layer. Thus, a polymeric film that is disposedover a light-emitting active region need not be formed directly on thelight-emitting active region. For example, the polymeric film can beformed on one of the electrodes between which the light-emitting activeregion is disposed, on an inorganic barrier layer that forms part of anencapsulation stack, and/or on the surface of an OLED support substrate.

Regarding the various deposition techniques that can be used to applythe curable ink compositions, an industrial inkjet printing system thatcan be housed in an enclosure configured to provide a controlled processenvironment can be used. Inkjet printing for the deposition of thecurable ink compositions described herein can have several advantages.First, a range of vacuum processing operations can be eliminated, asinkjet-based fabrication can be performed at atmospheric pressure.Additionally, during an inkjet printing process, an ink composition canbe localized to cover portions of an electronic device substrate,including portions that are over and proximal to an active region, toeffectively encapsulate an active region, including the lateral edges ofthe active region. The targeted patterning using inkjet printing resultsin eliminating material waste, as well as eliminating additionalprocessing typically required to achieve patterning of an organic layer,as required, for example, by various masking techniques.

Various embodiments of the curable ink compositions of the presentteachings can be deposited by printing over a wide number of OLEDdevices, such as OLED display devices and OLED lighting devices, to forma uniform planarizing layer. Such ink compositions can be cured usingthermal processing (e.g. bake), by exposure to optical energy, (e.g., UVcure or infrared (IR) cure), or electron-beam curing. Some embodimentsof the ink compositions can be cured by UV radiation, including UVradiation in the wavelength range of between about 365 nm to about 420nm.

Regarding encapsulation stacks fabricated over an active region of anelectronic device, as depicted in the schematic section view of FIG. 1,electronic device 50 can be fabricated on substrate 52. Variousembodiments of a substrate can include a thin silica-based glass, aswell as any of a number of flexible polymeric materials. For example,substrate 52 can be transparent, such as for use in a bottom-emittingoptoelectronic device (e.g. OLED) configuration. One or more layersassociated with an electronic device stack, such as various organic orother material can be deposited, inkjet printed, or otherwise formedupon the substrate to provide an active region 54, such as anelectroluminescent region in an OLED. Note that active region 54 in FIG.1 is illustrated schematically as a single block, but can in detailfurther include a region having complex topology or structure withmultiple discrete devices and film layers. In an example, if electronicdevice 50 is an OLED device, in can include an emissive layer, or otherlayers, coupled to an anode electrode and a cathode electrode. An anodeelectrode or a cathode electrode can be coupled to or can includeelectrode portion 56 that is laterally offset along the substrate 52from the active region 54.

As depicted in the illustrative embodiment of FIG. 1, an inorganicbarrier layer 60A can be provided on electronic device 50 over activeregion 54. For example, the inorganic barrier layer can be blanketcoated (e.g., deposited) over an entirety, or substantially an entiretyof a surface of the substrate 52, including active region 54, using, byway of a non-limiting example, plasma enhanced chemical vapor deposition(PECVD). Examples of inorganic materials useful for fabricatinginorganic barrier layer 60A can include various inorganic oxides, suchas one or more of Al₂O₃, TiO₂, HfO₂, SiO_(x)N_(y), inorganic nitrides,or one or more other materials. Adjacent to inorganic barrier layer 60Ais polymeric film 62A. As previously discussed herein, polymeric film62A can be deposited using for example, inkjet printing of a curable inkcomposition and then curing the ink composition to form the polymericfilm. Polymeric film 62A can serve as a planarizing layer to planarizeand mechanically protect the active region 54, as part of anencapsulation stack that collectively serves to suppress or inhibitmoisture or gas permeation into the active region 54. FIG. 1 illustratesgenerally a multilayered encapsulation stack configuration havinginorganic barrier layer 60A polymeric film 62A, a second inorganicbarrier layer 60B, and a second polymeric film 62B. Without being boundby theory or explanation, the planarizing layers in an encapsulationstack can serve to prevent the propagation of defects from one inorganicbarrier layer into an adjacent inorganic barrier layer. As such, variousembodiments of encapsulation stacks can be created to provide themechanical and sealing properties desired for an electronic device. Theorder of the fabrication of the layers in the encapsulation stackdepicted in FIG. 1 could be reversed, so that a polymeric planarizinglayer is first fabricated, followed by the fabrication of an inorganicbarrier layer. Additionally, greater or fewer numbers of dyads can bepresent. For example, a stack having inorganic barrier layers 60A and60B as shown, and a single polymeric planarizing layer 62A can befabricated.

As will be discussed in more detail herein, the present inventors haverecognized the need for curable ink compositions that that can be usedto form polymeric films that remain stable throughout the electronicdevice fabrication processes, as well as providing long-term stabilityand function as part of a protective layer for various electronicdevices.

Curable Ink Compositions for Thin Film Formation

Curable ink compositions of the present teachings can be readilydeposited as a liquid material on a substrate and then cured to form apolymeric thin film thereupon. Such curable ink compositions can includediacrylate monomers, dimethacrylate monomers, monoacrylate monomers,monomethacrylate monomers, and combinations thereof, as well as variousmultifunctional crosslinking agents. As used herein, the phrase“(meth)acrylate” indicates that the recited component may be anacrylate, methacrylate, or combinations thereof. For example, the term“(meth)acrylate monomer” refers to both methacrylate monomers andacrylate monomers. Various embodiments of the curable ink compositionsfurther include curing kinetics control additives and/or cureinitiators.

The compositions described herein are referred to as “ink compositions”because various embodiments of the compositions can be applied usingtechniques, including printing techniques, by which conventional inkshave been applied to substrates. Such printing techniques include, forexample, inkjet printing, screen printing, thermal transfer printing,flexographic printing, and/or offset printing. However, variousembodiments of the ink compositions can also be applied using othercoating techniques, such as, for example, spray coating, spin coating,and the like. Moreover, the ink compositions need not contain colorants,such as dyes and pigments, which are present in some conventional inkcompositions.

Some of the deposition techniques by which the ink compositions can beapplied include precision deposition techniques. Precision depositiontechniques are techniques that apply the ink compositions to a substratewith a high degree of precision and accuracy with respect to thequantity, location, shape, and/or dimensions of the printed inkcompositions and the cured polymeric films that are formed therefrom.The precision deposition techniques are able to form blanket coatings ofthe ink compositions or patterned coatings of the ink compositions that,once cured, form thin polymeric films with highly uniform thicknessesand well-defined edges. As a result, the precision deposition coatingtechniques are able to provide thin polymeric films that meet therequirements of a variety of organic electronic and organicoptoelectronic device applications. The required quantity, location,shape, and dimensions for a given precision deposited ink compositionand the cured film formed therefrom, will depend on the intended deviceapplication. By way of illustration, various embodiments of theprecision deposition techniques are able to form blanket or patternedfilms having a thickness of no greater than 10 μm with a thicknessvariation of no more than 5% across the film. Inkjet printing in oneexample of a precision deposition technique.

The ink compositions include at least one (meth)acrylate-based monomer,at least one multifunctional crosslinking agent, and at least one cureinitiator. Optionally, the ink compositions may further include at leastone curing kinetics control additive, at least one monofunctional(meth)acrylate (also referred to as a mono(meth)acrylate), or both.

Various embodiments of the ink compositions can be formed into curedfilms using a variety of methods, including spin coating, spraying, andinkjet printing. Cured polymeric films made from the ink compositionsare stable and flexible. In addition, the ink compositions can beformulated to provide cured polymeric films with glass transitiontemperatures (T_(g)) that allow them to be subjected to variouspost-processing techniques. Having a sufficiently high T_(g) isdesirable for certain applications, such as applications where thepolymeric films are exposed to high temperature conditions. By way ofillustration, for some electronic devices, including OLEDs, is itstandard practice to test the stability of the devices by subjectingthem to accelerated reliability testing in which the polymeric filmwould be exposed to high humidity under elevated temperatures. Forexample, the devices may be subjected to testing at 60° C. and 90%relative humidity (RH) or at 85° C. and 85% RH. Additionally, the T_(g)of the polymeric films should be sufficiently high to withstand any hightemperature post-processing steps that are used to fabricate theelectronic devices into which they are incorporated. For example, if alayer of material, such as an inorganic barrier layer, is deposited overthe polymeric film the polymeric film should be stable enough towithstand the maximum deposition temperature for the inorganic material.By way of illustration, inorganic barrier layers can be deposited overpolymeric planarizing layers using plasma enhanced chemical vapordeposition (PECVD), which can require deposition temperatures of 80° C.or higher. In order to pass the tests or withstand the post-processing,the polymeric film should have a T_(g) that is higher than the testingor processing temperatures. For high temperature applications such asthese, the curable ink compositions can be formulated to provide a T_(g)of 80° C. or greater. This includes embodiments of ink compositions thatare formulated to provide a T_(g) of 85° C. or greater.

Some embodiments of the curable ink compositions include adi(meth)acrylate monomer, such as an alkyl di(meth)acrylate monomer,where the generalized structure of an alkyl di(meth)acrylate is givenby:

where n is 3 to 21 and R is H or CH₃.

For various embodiments of curable ink compositions of the presentteachings, the alkyl chain of an alkyl di(meth)acrylate monomer can havebetween 3 to 21 carbon atoms and in various compositions, moreoverbetween 3 to 14 carbon atoms. Various embodiments of curable inkcompositions of the present teachings can utilize an alkyldi(meth)acrylate monomer that can have an alkyl chain with between 6 to12 carbon atoms. As will be discussed subsequently in more detailherein, factors that can guide the selection of an alkyldi(meth)acrylate monomer can include the resulting viscosity of aformulation at a selected deposition temperature, as well as fallingwithin the range of a target surface tension.

An exemplary alkyl di(meth)acrylate monomer according to the presentteachings is 1, 12 dodecanediol dimethacrylate, having the structure asshown below:

Various embodiments of curable ink compositions of the present teachingscan include between about 57 mol. % to about 97 mol. % of an alkyldi(meth)acrylate monomer, such as 1, 12 dodecanediol dimethacrylate(DDMA) monomer, and further can include curable ink compositions thatcomprise about 71 mol. % to 93 mol. % of an alkyl di(meth)acrylatemonomer. However, other embodiments of the curable ink compositions havea dimethacrylate monomer concentration of less than 60 mol. %. Thisincludes embodiments of the curable ink compositions having adimethacrylate monomer concentration of no greater than 56 mol. %. Byway of illustration, some embodiments of the ink compositions have adimethacrylate concentration, for example, a DDMA concentration, in therange from 50 mol. % to 56 mol. %. These lower dimethacrylate monomerconcentrations can be used, for example, in ink compositions that have asubstantial concentration of diacrylate monomers, as discussed in moredetail below.

In addition to an alkyl di(meth)acrylate monomer, the curable inkcompositions of the present teachings can have a diurethanedi(meth)acrylate monomer component in the in the formulation. Ageneralized diurethane di(meth)acrylate monomer structure is given by:

where R is independently selected from H and CH₃

An exemplary diurethane di(meth)acrylate monomer according to thepresent teachings is diurethane dimethacrylate (DUDMA), having thegeneralized structure as shown below, can be included in curable inkcompositions of the present teachings:

where DUDMA can be a mixture of isomers in which R can be hydrogen (H)or methyl (CH₃) in essentially equal proportion. For various embodimentsof curable ink compositions of the present teachings, DUDMA can bebetween about 1 mol. % to about 20 mol. % of a composition.

In addition to, or instead of, dimethacrylate monomers, such as DDMA,the curable ink compositions can include one or more diacrylatemonomers. The inclusion of diacrylate monomers, which lack the pendantmethyl group of a dimethacrylate, can increase the elastic modulus ofthe cured polymeric films made from the curable ink compositions,relative to polymeric films made from curable ink compositions that lackthe diacrylate monomers. Therefore, ink composition that includediacrylates are suited for forming polymeric films on flexibleelectronic devices. In particular, polymeric film flexibility can beincreased by alkyl diacrylate monomers having long linear alkyl chains.By way of illustration, the alkyl chain of an alkyl diacrylate monomercan have 3 to 21 carbon atoms and in various compositions, moreoverbetween 3 to 14 carbon atoms. For example, embodiments of curable inkcompositions of the present teachings can utilize an alkyl diacrylatemonomer that can have an alkyl chain having between 6 to 12 carbonatoms. Exemplary alkyl diacrylate monomers according to the presentteachings include 1, 10-decanediol diacrylate (DEDA), 1, 12-dodecanedioldiacrylate (DODA), hexanediol diacrylate, and combinations of two ormore thereof. Because the T_(g) of the cured polymeric films made usingthe ink compositions tends to increase with the decreasing alkyl chainlength of the diacrylates, it may be advantageous to include diacrylateshaving shorter alkyl chain lengths for electronic devices in which ahigher T_(g) is desirable. Another exemplary alkyl diacrylate monomeraccording to the present teachings istricyclo[5.2.1.02,6]decanedimethanol diacrylate, which has the followingstructure:

Some embodiments of the curable ink compositions are free ofdimethacrylate monomers, while other embodiments include a mixture ofdimethacrylate monomers and diacrylate monomers. In various embodimentsof the ink compositions that include the diacrylate monomers, theconcentration of diacrylate monomers is at least 30 mol. %. By way ofillustration, some embodiments of the ink compositions have a diacrylatemonomer concentration in the range from 30 mol. % to 40 mol. %,including in the range from 31 mol. % to 37 mol. %.

The diacrylates tend to be more reactive than their dimethacrylatecounterparts, and alkyl diacrylates tend to become more reactive withdecreasing alkyl chain length. This increased reactivity can result in afaster cure rate for the polymeric films formed from the inkcompositions. As discussed below, for certain applications, a fast curemay be undesirable. For such applications, ink compositions that includea mixture of dimethacrylates and diacrylates and/or that include alkyldiacrylates having longer alkyl chains (e.g., alkyl chains of nine ormore carbon atoms) may be used. In addition, one or more curing kineticscontrol additives can be included in the ink compositions in order toreduce their rate of cure.

As the ink compositions cure, they undergo a rapid viscosity increaseonce the gel point is reached due to bulk network formation and,ultimately, become vitrified. Bulk network formation and vitrificationrestrict the movement of polymer chain segments and monomer diffusion inthe composition. This can lead to high internal stress build up in thecuring film, causing significant kinetic instability of the polymernetwork, low flexibility, as characterized by high elastic modulus (highratio of Stress/Strain), and/or delamination of the cured film from anunderlying substrate. By adding curing kinetics control additives to thecurable ink compositions, the rate of curing can be decreased and thetime it takes to reach the gel point and/or vitrification can belengthened. As a result, the stress build-up in the cured polymericfilms made from the ink compositions can be reduced to provide a curedfilm that is more stable, more flexible, or both. The use of curingkinetics control additives may be particularly advantageous forapplications and industries where high intensity UV light is routinelyused to cure the compositions.

The curing kinetics control additives share the common characteristicthat they increase an ink composition's time to reach gel point and/orvitrification onset, relative to that of an ink composition that doesnot include the curing kinetics control additives, but is otherwise thesame ink composition. However, the curing kinetics control additives canslow the rate of curing and increase the time to gel point and/orvitrification onset via different mechanisms.

In some embodiments of the curable ink compositions, the curing kineticscontrol additives are curable monomers that have a lower reactivity thanthe diacrylates and, in some cases the dimethacrylates, during thecuring of the ink compositions. Because these additives act as monomersduring polymerization, they are referred to as curing kinetics controlmonomers. Curable monofunctional monomers, including monofunctionalvinyl monomers and monofunctional (meth)acrylate monomers, are examplesof monomers that may have a lower reactivity during curing than thediacrylate monomers in a curable ink composition. Tert-butyl styrene(TBS) is an example of a vinyl styrene monomer that can be used as acuring kinetics control monomer. The monofunctional (meth)acrylates canbe, for example, alkyl monoacrylates and/or alkyl monomethacrylates.Because the reactivity of alkyl mono(meth)acrylates generally increaseswith decreasing alkyl chain length, suitable alkyl mono(meth)acrylatesinclude those having alkyl chains of at least nine, including at leastten, carbon atoms.

The use of monofunctional acrylates in the ink compositions may alsoprovide the cured polymeric films formed from the ink compositions witha lower elastic modulus and, therefore, a higher flexibility. In fact,monofunctional (meth)acrylates can be added to the curable inkcompositions for the purpose of decreasing the elastic modulus ofpolymeric films formed therefrom even if they do not act as curingkinetics control monomers. Lauryl acrylate is one example of amonofunctional acrylate that can be included in the ink compositions asa curing kinetics controls monomer and to decrease the elastic modulusof the polymeric films formed from the ink compositions.

The curing kinetics control additives can also be chain transfer agentsand/or radical trapping agents. Chain transfer agents (CTA), also calledmodifiers or regulators, have at least one weak chemical bond. Thesecompounds react with the free-radical site of a growing polymer chainand interrupt chain growth. In the process of chain transfer, theradical is temporarily transferred to the chain transfer agent whichreinitiates growth by transferring the radical to another polymer ormonomer. Such interruption of chain growth followed by radical transfer,and chain growth re-initiation reduces the average molecular weight ofgrowing polymer chains in a polymeric composition, and delays polymerchain propagation throughout the volume. This leads to the formation ofmicrogels (localized network formation) initially, rather than a bulkgelled network as curing process initiated. The result is a delayed gelpoint and delayed vitrification. Examples of chain transfer agentsand/or radical trapping agents that can be used as curing kineticscontrol additives include thiols, for example, dodecyl thiol; vinylstyrene derivatives, such as α-methyl styrene dimer (MSD) (also known as2,4-Diphenyl-4-methyl-1-pentene);

and cyclic terpenes, such as terpinolene (also known as4-Isopropylidene-1-methylcyclohexene, or p-Meth-1-en-8-yl-formate,p-Menth-1,4(8)-diene), dipentene (also known as limonene, orp-Mentha-1,8-diene), and gamma-terpinene (also known as1-Isopropyl-4-methyl-1,4-cyclohexadiene, or p-Mentha-1,4-diene).

Some embodiments of the ink compositions are free of halogenatedhydrocarbon chain transfer agents, as those can have harmful effects onunderlying device structures.

The concentration of the curing kinetics control additives in thecurable ink compositions will depend, at least in part, on the mechanismby which such additives increase the time to reach the gel point and/orvitrification.

Curing kinetics control monomers increase the vitrification time bylowering reactivity during cure, and can also decrease polymer chainbranching when monofunctional monomers are used, thus creating more openpolymer network formation. Such monomers usually have a relatively smalleffect on the gel point, while noticeably delaying vitrification of theforming polymer network. However, when chain transfer agents (CTA) thatreduce the average molecular weight of growing polymer chains are usedto control curing kinetics, they significantly delay both curing steps:a gel point; and vitrification of the forming polymer network. Delayedgelling of a curable formulation, which means extended time during whichan ink formulation remains liquid (non-gelled ink phase), allows for agreater stress release in a pre-forming polymer network (micro gels),resulting in much less stress buildup. A reduction in the averagemolecular weight of growing polymer chains also results in a slowerviscosity increase even after gelling occurs, which allows for slowerdecrease in diffusion of monomers throughout the forming polymernetwork, and a higher degree of double bonds conversion. Thus, CTAs canbe much more effective at controlling curing kinetics and decreasing theinternal stress buildup of a polymer network. They can also provide amore complete photoinitiator consumption due to a longer reaction time,and higher concentrations of forming radicals.

Generally, the concentration of a curing kinetics control monomer thatincreases the time to reach vitrification simply by virtue of having alower reactivity during cure, and/or decreased branching, will be in therange from 1 mol. % to 20 mol. %, while the concentration of a curingkinetics control additive that is a chain transfer agent will be lessthan 1 mol. %. For example, various embodiments of the ink compositionshave a curing kinetics control additive concentration in the range from0.2 mol. % to 5 mol. %; and more typically in the range from 0.2 mol. %to 2.5 mol. %. However, concentrations outside of these ranges can beused.

The degree to which the curing kinetics control additives increase thetime to reach the gel point, and the time to vitrification onset (alsoreferred to as the vitrification time) will depend on their particularcuring kinetics control mechanism as described above, and theirconcentration in the ink composition. For some embodiments of the inkcompositions, the addition of the curing kinetics control additivesincreases the time to reach the gel point or the time to reachvitrification by at least 40%. This includes embodiments of the inkcompositions for which the addition of the curing kinetics controladditives increases the time to reach the gel point or the time to reachvitrification by at least 100% and further includes embodiments of theink compositions for which the addition of the curing kinetics controladditives increases the time to reach the gel point or the time tovitrification by at least 200%. For the purposes of this disclosure, thevitrification time for an ink composition can be measured as the time toreach maximum curing rate for that ink composition, where the maximum inthe curing rate corresponds to the peak in a graph of the heat releasedby the composition during curing as a function of curing time.

A choice of particular curing kinetic control additives will depend onthe desired or required properties of the ink compositions and/or theintended method for their application, and on the desired or requiredproperties of the cured polymeric films made from the ink compositions.For example, an ink formulation may be well balanced in terms of itschemical composition for meeting the requirements of an intendedapplication and may have optimal physical properties (for example anoptimal viscosity and surface tension for inkjet printing). If thecuring kinetics of such a well-balanced composition have to be adjustedto prevent a stress buildup, then it may be advantageous to use CTAcuring kinetics control additives, since they are highly efficient evenat low quantities. Their low quantity will have a minimal impact on theink composition's chemical and physical properties but will result inthe formation of a polymeric film with reduced stress. Alternatively, ifit would be beneficial to incorporate significant quantities of acertain chemical functionalities into an ink composition, then lowerreactivity curing kinetic control monomers could be used, optionally incombination with one or more CTAs. For example, if rigid curing kineticscontrol additives are used, they can provide the additional advantage ofincreasing the T_(g) of the polymeric films formed by curing the curableink compositions. TBS is an example of a rigid curing kinetics controlmonomer that can be used for this purpose.

In addition to di(meth)acrylate monomers as previously described herein,various multifunctional (meth)acrylate monomer crosslinking agents canbe included in the curable ink compositions of the present teachings. Asan alternative to, or in addition to, the multifunctional (meth)acrylatecrosslinking agents, the curable ink compositions can include one ormore multifunctional vinyl siloxane crosslinking agents. As used herein,the term multifunctional crosslinking agent refers to a crosslinkingagent having at least three reactive crosslinkable groups. Thus, themultifunctional (meth)acrylate crosslinking agents can be, for example,tri(meth)acrylates, tetra(meth)acrylates, as well as higherfunctionality (meth)acrylates. For example, curable ink compositions ofthe present teachings can include trimethylolpropane tri(meth)acrylateand pentaerythritol tetra(meth)acrylate, as well as combinationsthereof. Vinyl siloxane crosslinking agents include cyclic vinylsiloxanes, such as2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (TMTVCTS). Forapplications where a flexibility and/or a high T_(g) is desired, higherfunctionality crosslinking agents, including crosslinking agents havefour or more crosslinkable groups may be used.

Curable ink compositions of the present teachings can includemultifunctional crosslinking agents at concentration in the range from,for example, 1 mol. % to 15 mol. %. This includes embodiments of the inkcompositions having a multifunctional crosslinking agent concentrationin the range from 5 mol. % to 10 mol. %. However, concentrations outsideof these ranges can be used. For example, a trimethylolpropanetri(meth)acrylate in a range of between about 1-13 mol. % of a curableink composition. In various curable ink composition of the presentteachings, a pentaerythritol tetra(meth)acrylate monomer can be includedin a range of between about 3-10 mol. % of a composition.

A generalized structure of a tri-functional tri(meth)acrylate monomer,trimethylolpropane tri(meth)acrylate, is shown below:

where R is independently selected from H and CH₃

An exemplary trimethylolpropane tri(meth)acrylate for variousembodiments of a curable ink composition of the present teachings istrimethylolpropane triacrylate, the structure of which is given below:

A generalized structure of a tetra-functional tetra(meth)acrylatemonomer, pentaerythritol tetra(meth)acrylate, is shown below:

where R is independently selected from H and CH₃

An exemplary pentaerythritol tetra(meth)acrylate of the presentteachings, pentaerythritol tetraacrylate, is shown below:

With respect to the initiation of the curing process, variousembodiments of the curable ink compositions of the present teachings canutilize numerous types of cure initiators for initiating polymerization.Suitable cure initiators include photoinitiators (PIs), thermalinitiators, and initiators that induce polymerization using other typesof energy, such as electron beam initiators. In some embodiments of theink compositions, photoinitiators are used. In these embodiments thephotoinitiators may be present in amounts in the range from about 1 mol.% to about 10 mol. %. This includes embodiments in which thephotoinitiators are present in amounts in the range from about 2 mol. %to about 6 mol. %. However, amounts outside of these ranges can also beused. The photoinitiator may be a Type I or a Type II photoinitiator.Type I photoinitiators undergo radiation-induced cleavage to generatetwo free radicals, one of which is reactive and initiatespolymerization. Type II photoinitiators undergo a radiation-inducedconversion into an excited triplet state. The molecules in the excitedtriplet state then react with molecules in the ground state to producepolymerization initiating radicals.

The specific photoinitiators used for a given curable ink compositionare desirably selected such that they are activated at wavelengths thatare not damaging to the OLED materials. For this reason, variousembodiments of the curable ink compositions include photoinitiators thathave a primary absorbance with a peak in the range from about 365 nm toabout 420 nm. The light source used to activate the photoinitiators andinduce the curing of the curable ink compositions is desirably selectedsuch that the absorbance range of the photoinitiator matches or overlapswith the output of the light source, whereby absorption of the lightcreates free radicals that initiate polymerization. Suitable lightsources may include mercury arc lamps and light emitting diodes.

An acylphosphine oxide photoinitiator can be used, though it is to beunderstood that a wide variety of photoinitiators can be used. Forexample, but not limited by, photoinitiators from the a-hydroxyketone,phenylglyoxylate, and a-aminoketone classes of photoinitiators can alsobe considered. For initiating a free-radical based polymerization,various classes of photoinitiators can have an absorption profile ofbetween about 200 nm to about 400 nm. For various embodiments of thecurable ink compositions and methods of printing disclosed herein,2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and2,4,6-trimethylbenzoyl-diphenyl phosphinate have desirable properties.For various embodiments of the curable ink compositions and printingmethods of the present teaching, an acylphosphine oxide photoinitiatorcan be about 0.1-5 mol. % of a formulation. Examples of acylphosphinephotoinitiators include Omnirad® TPO (also previously available underthe tradename Lucirin® TPO) initiators for curing with optical energy inthe wavelength range of about 365 nm to about 420 nm sold under thetradenames Omnirad® TPO, a type I hemolytic initiator which; withabsorption @380 nm; Omnirad® TPO-L, a type I photoinitiator that absorbsat 380 nm; and Omnirad® 819 with absorption at 370 nm. By way ofnon-limiting example, a light source emitting at a nominal wavelength inthe range from 350 nm to 395 nm at a radiant energy density of up to 2.0J/cm² could be used to cure a curable ink composition comprising a TPOphotoinitiator. Using the appropriate energy sources, high levels ofcuring can be achieved. For example, some embodiments of the cured filmshave a degree of curing of 90% or greater, as measured by FourierTransform Infrared (FTIR) spectroscopy.

Tables 1 through 7, shown below, summarize various components, as wellas ranges for the components, for four non-limiting exemplary curableink compositions of the present teachings.

TABLE 1 Summary of composition for Formulation I, including componentranges Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate (DDMA)57-97 Diurethane Dimethacrylate (DUDMA)  1-20 TrimethylolpropaneTriacrylate (TMPTA)  1-13 Ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate (TPO)  1-10

TABLE 2 Summary of composition for Formulation II, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA) 64-97 Pentaerythritol tetraacrylate (PET)  1-13Trimethylolpropane Triacrylate (TMPTA)  1-13 Ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate (TPO)  1-10

TABLE 3 Summary of composition for Formulation III, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA)  50-56 1, 10-decanediol diacrylate (DEDA)  31-37 α-methyl styrenedimer (MSD) 0.2-5  Trimethylolpropane Triacrylate (TMPTA)   1-10 Ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate (TPO) 0.5-5 

TABLE 4 Summary of composition for Formulation IV, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA)  50-56 1, 10-decanediol diacrylate (DEDA)  31-37 α-methyl styrenedimer (MSD) 0.2-5  Trimethylolpropane Triacrylate (TMPTA)   1-102,4,6,8-tetramethyl-2,4,6,8-tetrayinylcyclotetrasiloxane 0.2-5 (TMTVCTS) Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO) 0.5-5 

TABLE 5 Summary of composition for Formulation V, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA)  50-56 1, 10-decanediol diacrylate (DEDA)   1-20Tricyclodecanedimethanol Diacrylate (TCDDA)   1-20 a-methyl styrenedimer (MSD) 0.2-5  Trimethylolpropane Triacrylate (TMPTA)   1-10 Ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate (TPO) 0.5-5 

TABLE 6 Summary of composition for Formulation V1, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA)  50-56 Tricyclodecanedimethanol Diacrylate (TCDDA)   5-40a-methyl styrene dimer (MSD) 0.2-5  Trimethylol propane Triacrylate(TMPTA)   1-10 Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO)0.5-5 

TABLE 7 Summary of composition for Formulation VII, including componentranges. Mol. % Component (Range) 1, 12 Dodecanediol Dimethacrylate(DDMA)  50-56 Tricyclodecanedimethanol Diacrylate (TCDDA)   5-40Trimethylolpropane Triacrylate (TMPTA)   1-10 Ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate (TPO) 0.5-5 

Some embodiments of the curable ink compositions of the presentteachings are formulated to provide stability during processing of theformation of a complete encapsulation stack fabricated upon an OLEDdevice, as well as long-term stability for the effective sealing of thedevice over its useful lifetime. Additionally, curable ink compositionsof the present teachings are formulated to provide function, such asflexibility, and optical properties, such as to enhance the use of anOLED device. For example, in Formulations I through IV an alkyldi(meth)acrylate monomer, such as DDMA, in conjunction with a selectionof cross-linking agents, such as PET and TMPTA, can provide an organicplanarizing layer with a hydrophobic property and high cross-linkingdensity. However, other polymer film properties may also be importantfor an encapsulation stack or another electronic device, such asproviding flexibility for OLEDs and other devices that can be repeatedlybent, rolled, or otherwise flexed. The selection of the types andamounts of components can be done according to the present teachings, toprovide for films that are mechanically durable and at the same timeflexible. By way of a non-limiting example, in Formulation I, thediurethane di(meth)acrylate monomer, DUDMA, can be used in conjunctionwith an alkyl di(meth)acrylate monomer in ranges as given in Table 1 toprovide for organic encapsulation stacks that have reduced stress andprovide for targeted polymer film flexibility. In another non-limitingexample, in Formulation II, a mixture of trifunctional andtetra-functional crosslinking agents can be used to provide formechanical strength and desired degree of polymer crosslinking, and atthe same time render sufficient segment mobility within the polymernetwork to provide for targeted polymer film flexibility.

Properties of liquid curable ink compositions that can be tailored tomeet the requirements of a given device application include viscosity,surface tension and water content. A summary of viscosity, surfacetension and water content determinations for Formulation I andFormulation II is given in Table 5 below:

TABLE 5 Properties of exemplary organic polymer formulations SurfaceTension ± SD Composition Viscosity ± SD (Dynes/cm Water ID (cP at 25°C.) at 25° C.) (ppm) ± SD Formulation I 25.6 ± 0.47 38.9 ± 0.21 73 ± 26(N = 10) (N = 10) (N = 10) Formulation II 16.09 ± 0.30 (N = 8) 37.7 ±0.20 (N = 8) 36 ± 9 (N = 8)

With respect to properties of curable ink compositions of the presentteachings, generally, for use for inkjet printing applications, thesurface tension, viscosity and wetting properties of the curable inkcompositions should be tailored to allow the compositions to bedispensed through an inkjet printing nozzle without drying onto orclogging the nozzle at the temperature used for printing (e.g., roomtemperature; ca. 25° C.). Once formulated, various embodiments of thecurable ink compositions can have a viscosity of between about 10 cP andabout 28 cP (including, for example, between about 15 cP and about 26cP) at 25° C. and a surface tension of between about 28 dynes/cm andabout 45 dynes/cm at 25° C. As will be discussed in more detail herein,it is desirable to keep the water content as determined by the KarlFischer titrimetric method to less than 100 ppm, which as shown in Table5 was readily met in analysis of Formulation I and Formulation II.

FIG. 2 illustrates generally a graph of viscosity as a function oftemperature for Formulation I, while FIG. 3 illustrates generally agraph of viscosity as a function of temperature for Formulation II.Jetting temperatures can be between about 20° C. to about 50° C.,including temperatures between 22° C. to about 40° C. As can be seen byinspection of the graphs presented in FIG. 2 and FIG. 3, over suchtemperature ranges, various embodiments of organic polymer formulationscan have a viscosity of between about 7-25 cP; including, for example,between about 9 cP and about 19 cP.

Preparation, Drying and Storage of Curable Ink Compositions

Given that the initiation of polymerization can be induced by light,curable ink compositions can be prepared to prevent exposure to light.With respect to the preparation of the curable ink compositions of thepresent teachings, in order to ensure the stability of variouscompositions, the compositions can be prepared in a dark or very dimlylit room or in a facility in which the lighting is controlled to excludewavelengths that would induce polymerization. Such wavelengths generallyinclude those below about 500 nm. For example, for the preparation of anembodiment of an organic polymer formulation, in a fashion that protectsthe direct exposure to light, the lid of a clean amber vial (forexample, Falcons, VWR trace clean) can be removed and then can be placedon a balance; and tared. First, a desired amount of a photoinitiator canbe weighed into the vial. Then, the dimethacrylate and/or diacrylate canbe weighed into the vial. Next, the mono(meth)acrylate monomer can beweighed into the vial. Finally, the crosslinking agent can be weighedinto the vial. (The preceding description lays out one protocol forsequentially incorporating the various components into a curable inkcomposition. Other protocols can be used.) Regarding mixing to provideuniform concentration of components, a Teflon® coated magnetic stir barcan be inserted into the vial and the cap of vial secured. The solutioncan then be stirred, for example, for 30 minutes at temperatures in therange from room temperature to 50° C. and 600-1000 rpm.

Once the curable ink compositions are prepared, they can be dehydratedby mixing in the presence of a 10 wt. % 3A molecular sieve beads for aperiod of several hours or more to yield <100 ppm moisture and thenstored under a dry, inert atmosphere, such as a compressed dry airatmosphere. Thereafter, the curable ink composition can be filtered, forexample, through a 0.1 am or 0.45 am PTFE syringe filter or vacuum orpressure filter, followed by sonication for 30 minutes at ambienttemperature to remove residual gases. The curable ink composition isthen ready for use and should be stored away in a dark cool environment.Various embodiments of an organic thin film organic polymer preparationas described can have a viscosity of between about 10 cps and about 30cP at 22° C. and a surface tension of between about 34 dynes/cm andabout 40 dynes/cm at 22° C.

The curable ink compositions, particularly those stored under a dry,inert atmosphere at room temperature (22° C.), can be stable for longperiods of time, as determined by the lack of precipitation or gelationunder visual inspection and the stabilities in their room temperatureviscosities and surface tensions. No significant changes were recordedin viscosity and surface tension of the curable ink compositions ofFormulations I and II; any changes are deemed to be within measurementerrors for at least 160 days at room temperature under compressed dryair atmosphere in the dark.

Properties of Thin Films Formed Using Exemplary Formulations

After curing, continuous polymeric films having thicknesses of betweenabout 2 am to about 10 am were successfully fabricated on varioussubstrates using Formulation I and Formulation II. Film propertiesincluding percent volume shrinkage, degree of curing, optical haze,optical transmission and color were evaluated for films formed usingFormulation I and Formulation II. The results of the evaluation of suchproperties for Formulation I and Formulation II are presented in Table 6and Table 7, shown below, as well as in FIG. 5.

TABLE 6 Summary of selected properties of films formed from exemplaryformulations. Shrinkage Curing Degree Haze (%) ± SD (%) ± SD % ± SDComposition (N = 3) (N = 3) (N = 3)¹ Formulation I 9.55 ± 0.09 87.90 ±0.12 0.033 ± 0.005 Formulation II 9.93 ± 0.29 87.70 ± 0.03 0.043 ± 0.005¹compared to glass reference of 0.083 ± 0.005

TABLE 7 Summary of Lab color space properties of films formed fromexemplary formulations. Film from Film from Glass Formulation IFormulation II Reference Source Mean Std. Mean Std. Mean Std. Attribute(N = 3) Dev. (N = 3) Dev. (N = 3) Dev. L* 96.83 0 96.83 0 96.93 0 a*−0.013 0 0.003 0 0.003 0 b* 0.32 0.01 0.33 0.01 0.15 0.005

In Table 6, film shrinkage is evaluated using a UV rheometer designed tofollow the curing progress from onset of irradiation of the sample to afully cured state, and the degree of curing is determined using FTIRanalysis. For polymeric planarization films from curable inkcompositions of the present teachings, shrinkage of less than about 12%and degree of curing of between about 85%-90% are target values forthose properties.

Optical properties of films formed from curable ink composition of thepresent teachings for various OLED devices include haze, percent opticaltransmission through a desired wavelength range, and color. As haze is ameasure of the fraction of transmitted wide angle scattered light from asource that is transmitted through a film, a low percent haze isdesirable for a polymeric planarizing layer. As such, a target for hazenot to exceed 0.10% is clearly met by films formed from Formulation Iand Formulation II. As can be seen in the graph presented in FIG. 4, thepercent transmission of light in a wavelength range of between about 350nm to about 750 nm for films formed from Formulation I and FormulationII is comparable to that of a glass reference. Finally, regarding color,it is desirable for films formed from Formulation I and Formulation IInot to act as a color filter. Color space as defined by CIELAB, definesa value of L*=100 as the brightness of the object measured, while a* isa measure of chromaticity of red and green, and b is a measure of thechromaticity of yellow and blue. In that regard, for films formed fromFormulation I and Formulation II, it is desirable for L* to be greater95, while it is desirable for a* and b* to be less than 0.5. In thatregard, as can be seen by inspection of Table 7, the analysis ofrepresentative films formed using Formulation I and Formulation II donot exceed these values, which is consistent with the opticaltransmission graph shown in FIG. 4.

Systems and Methods for Organic Thin Film Formation on a Substrate

Various embodiments of formulations of the present teachings can beprinted using an industrial inkjet printing system that can be housed inan enclosure defining an interior that has a controlled processenvironment. For example, a controlled process environment of thepresent teachings can include a process environment that is non-reactiveto materials that are used in the fabrication of, for example, variousOLED devices, as well as being a substantially low-particle processenvironment. Patterned printing of an organic thin film on an OLEDdevice substrate in such a controlled environment can provide forhigh-volume, high yield processes for a variety of OLED devices, such asOLED display and lighting devices.

Curable ink compositions of the present teachings can be printed using aprinting system, such as described in U.S. Pat. No. 9,343,678, issuedMay 17, 2016, which is incorporated herein in its entirety. Variousembodiments of the present organic polymer compositions can be inkjetprinted into thin films that are continuous and have well-defined edgeson such substrates as glass, plastics, silicon, and silicon nitride. Forexample, the organic polymer compositions can be used to print thinfilms having thicknesses in the range from about 2 am to about 10 am, orthicker, including thin films having thicknesses in the range from about2 am to about 8 am. These thin films can be achieved with film thicknessvariation of, for example, 5% or lower.

Gas enclosure system 500 of FIG. 5 can include gas enclosure 1000 forhousing printing system 2000. Printing system 2000 can be supported byprinting system base 2150, which can be a granite stage. Printing systembase 2150 can support a substrate support apparatus, such as a chuck,for example, but not limited by, a vacuum chuck, a substrate floatationchuck having pressure ports, and a substrate floatation chuck havingvacuum and pressure ports. In various examples of the present teachings,a substrate support apparatus can be a substrate floatation table, suchas substrate floatation table 2250. Substrate floatation table 2250 canbe used to float a substrate during frictionless transport of thesubstrate. In addition to a low-particle generating floatation table,for frictionless Y-axis conveyance of a substrate, printing system 2000can have a Y-axis motion system utilizing air bushings.

FIG. 5 illustrates generally an example of gas enclosure system 500 ofmanufacturing system 3000A configured with external gas loop 3200 forintegrating and controlling gas sources, such as a source of CDA and asource of a non-reactive gas such as can be used to establish acontrolled process environment for various enclosed manufacturingsystems of the present teachings, as well as providing a source of gasfor operating various pneumatically controlled devices. According to thepresent teachings, a non-reactive gas can be any gas that does notundergo a chemical reaction with materials used in the manufacture ofOLED devices, such as display and lighting devices, under processconditions. In various embodiments, a non-reactive gas can be anon-oxidizing gas. Some non-limiting examples of non-reactive gas thatcan be used include nitrogen, any of the noble gases, and anycombination thereof. As will be discussed in more detail herein blowerloop 3280 can provide pressurized gas and at least partial vacuum foruse with a floatation table 2250. Additionally, as depicted in FIG. 5,gas enclosure system 500 can be generally configured so that a pressureof gas inside the gas enclosure 1000 can be maintained within a desiredor specified range, such as using a valve coupled to a pressure monitor,P.

Gas enclosure system 500 can also be configured with various embodimentsof a gas purification system that can be configured for purifyingvarious reactive species from a non-reactive process gas. A gaspurification system according to the present teachings can maintainlevels for each species of various reactive species, such as watervapor, oxygen, ozone, as well as organic solvent vapors, for example, at100 ppm or lower, at 10 ppm or lower, at 1.0 ppm or lower, or at 0.1 ppmor lower. Gas enclosure system 500 can also be configured with variousembodiments of a circulation and filtration system for maintaining asubstantially particle free environment. Various embodiments of aparticle filtration system can maintain a low particle environmentwithin a gas enclosure meeting the standards of International StandardsOrganization Standard (ISO) 14644-1:1999, “Cleanrooms and associatedcontrolled environments—Part 1: Classification of air cleanliness,” asspecified by Class 1 through Class 5.

Substrate floatation table is depicted in FIG. 5 as being in flowcommunication with blower loop 3280. Blower loop 3280 can include blowerhousing 3282, which can enclose first blower 3284 for supplying apressurized source of gas to substrate floatation table 2250 via line3286, and second blower 3290, acting as a vacuum source for substratefloatation table 2250 via line 3292, providing at least partial vacuumto substrate floatation table 2250. Various embodiments of blower loop3280 can be, configured with heat exchanger 3288 for maintaining gasfrom blower loop 3280 to substrate floatation table 2250 at a definedtemperature.

As depicted in FIG. 5, non-reactive gas source 3201 can be in flowcommunication with low consumption manifold line 3212 via non-reactivegas line 3210. Low consumption manifold line 3212 is shown in flowcommunication with low consumption manifold 3215. Cross-line 3214extends from a first flow juncture 3216, which is located at theintersection of non-reactive gas line 3210, low consumption manifoldline 3212, and cross-line 3214. Cross-line 3214 extends to a second flowjuncture 3226. CDA line 3222 extends from a CDA source 3203 andcontinues as high consumption manifold line 3224, which is in fluidcommunication with high consumption manifold 3225. As will be discussedin more detail herein, CDA can be used during, for example, maintenanceprocedures. During processing, non-reactive gas source 3201 can be inflow communication with low consumption manifold 3215 and highconsumption manifold 3225. As such, during processing non-reactive gassource can be routed through external gas loop 3200 to providenon-reactive gas to gas enclosure 1000, as well as providingnon-reactive gas for operating various pneumatically operatedapparatuses and devices used during the operation of printing system2000. For example, high consumption manifold 3225 can providenon-reactive gas from gas source 3201 during processing for theoperation of various components for printing system 2000 housed in gasenclosure 1000, such as, but not limited by, one or more of a pneumaticrobot, a substrate floatation table, an air bearing, an air bushing, acompressed gas tool, a pneumatic actuator, and combinations thereof.

Regarding the use of CDA, for example, during a maintenance procedure,second flow juncture 3226 is positioned at the intersection of across-line 3214, clean dry air line 3222, and high consumption manifoldline 3224, which is in flow communication with high consumption manifold3225. Cross-line 3214 extends from a first flow juncture 3216, which isin flow communication with non-reactive gas line 3210, which flowcommunication can be controlled by valve 3208. During a maintenanceprocedure, valve 3208 can be closed to prevent flow communicationbetween non-reactive gas source 3201 and high consumption manifold 3225,while valve 3206 can be opened thereby allowing flow communicationbetween CDA source 3203 and high consumption manifold 3225. Under suchconditions, various components that are high consumption can be suppliedCDA during maintenance.

With respect to controlling the pressure of gas inside the gas enclosure1000, as depicted in FIG. 5, such regulation can assist in maintaining aslight positive internal pressure of a gas enclosure system, which canbe between about 2-12 mbar above the pressure in the environmentexternal a gas enclosure. Maintaining the internal pressure of a gasenclosure at a desired slightly positive pressure versus an externalpressure is necessary given that pressurized gas is alsocontemporaneously introduced into the gas enclosure system. Variabledemand of various devices and apparatuses can create an irregularpressure profile for various gas enclosure assemblies and systems of thepresent teachings. The internal pressure of a gas enclosure can bemaintained within a desired or specified range, by using a controlsystem configured with a valve coupled to a pressure monitor, P, wherethe valve allows gas to be exhausted to another enclosure, system, or aregion surrounding the gas enclosure 1000 using information obtainedfrom the pressure monitor. Exhausted gas can be recovered andre-processed through gas circulation and purification systems aspreviously described herein.

FIG. 6 illustrates generally an isometric view of a manufacturing system3000B, such as including a first printing system 2000A, a secondprinting system 2000B and first curing system 1300A and second curingsystem 1300B as well other enclosed modules, that can be used inmanufacturing various optoelectronic devices (e.g., an organic lightemitting diode (OLED) device). First and second curing systems 1300A and1300B of the present teachings can be used for one or more of holding asubstrate (e.g., to facilitate flowing or dispersing the depositedmaterial layer, such as to achieve a more planar or uniform film), aswell as curing (e.g. via optical illumination in wavelength a wavelengthrange of about 365 nm to about 420 nm) a layer of material, such asdeposited by one or more of the first or second printing systems 2000Aand 2000B. For example, a material layer that flows or disperses, or iscured, using the first and second processing systems 1300A and 1300B caninclude a portion of an encapsulation stack (such as a thin film layercomprising an organic thin film material that can cured or treated viaexposure to optical energy). The first or second processing systems1300A or 1300B can be configured for holding substrates, such as in astacked configuration. The first and second printers 2000A and 2000B canbe used, for example, to deposit the same layers on a substrate orprinters 2000A and 2000B can be used to deposit different layers on asubstrate.

Manufacturing system 3000B can include an input or output module 1101(e.g., a “loading module”), such as can be used as a load-lock orotherwise in a manner that allows transfer of a substrate into or out ofan interior of one or more chambers of manufacturing system 3000B in amanner that substantially avoids disruption of a controlled environmentmaintained within one or more enclosures of manufacturing system 3000B.For example, in relation to FIG. 6, “substantially avoids disruption”can refer to avoiding raising a concentration of a reactive species by aspecified amount, such as avoiding raising such a species by more than10 parts per million, 100 parts per million, or 1000 parts per millionwithin the one or more enclosures during or after a transfer operationof a substrate into or out the one or more enclosures. A transfermodule, such as can include a handler, can be used to manipulate asubstrate before, during, or after various operations.

Various examples described herein include enclosed processing systemsthat can be environmentally-controlled. Enclosure assemblies andcorresponding support equipment can be referred to as a “gas enclosuresystem” and such enclosure assemblies can be constructed in a contouredfashion that reduces or minimizes an internal volume of a gas enclosureassembly, and at the same time provides a working volume foraccommodating various footprints of a manufacturing system of thepresent teachings, such as the deposition (e.g., printing), holding,loading, curing systems or modules described herein. For example, acontoured gas enclosure assembly according to the present teachings canhave a gas enclosure volume of between about 6 m³ to about 95 m³ forvarious examples of a gas enclosure assembly of the present teachingscovering, for example, substrate sizes from Gen 3.5 to Gen 10. Variousexamples of a contoured gas enclosure assembly according to the presentteachings can have a gas enclosure volume of, for example, but notlimited by, of between about 15 m³ to about 30 m³, which might be usefulfor printing of, for example, Gen 5.5 to Gen 8.5 substrate sizes above,or other substrate sizes that can readily be derived therefrom.

FIG. 7 depicts flow diagram 100 that illustrates generally a process forthe fabrication of an organic thin films on various device substrates.FIG. 7 illustrates techniques, such as methods, that can include formingan organic thin-film planarizing layer over the active area a lightemitting device (e.g., an of a OLED lighting or display device) formedon a substrate, such as for providing a mura-free organic thin filmlayer. At 110, a substrate can be transferred onto a substrate supportsystem of an enclosed printing system configured to provide a controlledprocess environment as previously described herein. A substrate can betransferred to an enclosed printing system from, for example, aninorganic thin film encapsulation system. As previously describedherein, a substrate support system can be configured to provide uniformsupport of the substrate at least in one or more active regions of thesubstrate. Such a substrate support system can include a floatationtable configuration, such as having various floatation control zonesincluding one or more of a pneumatically-supplied gas cushion, or acombination of pneumatic and at least partial vacuum supplied regions toprovide a gas cushion supporting the substrate. At 120, a curable inkcomposition can be printed over a target deposition region of asubstrate. At 130, the substrate can be transferred from an enclosedprinting system to an enclosed curing system configured to provide acontrolled process environment as previously described herein. Accordingto the present teachings, for example, a curing system can provide anapparatus that can uniformly illuminate a substrate or portion or asubstrate with optical energy in a wavelength range from about 365 nm toabout 420 nm. At 140, a curing system can have a substrate supportsystem that can provide a pneumatically supplied gas cushion, or acombination of pneumatic and at least partial vacuum supplied regions toprovide a gas cushion supporting the substrate uniformly in a mannerthat can suppress or inhibit mura formation during one or more of aholding operation or curing operation. For example, the substrate can beheld for a specified duration after printing and before curing, such asbefore an optical curing process is initiated. At 150, the liquidorganic polymer layer can be cured, for example, using an opticaltreatment provided within an enclosed curing system, such as to providea mura-free organic thin film encapsulation layer.

The present teachings are intended to be illustrative, and notrestrictive. It is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Also, inthe above Detailed Description, various features may be grouped togetherto streamline the disclosure. This should not be interpreted asintending that an unclaimed disclosed feature is essential to any claim.Rather, inventive subject matter may lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description as examples or embodiments,with each claim standing on its own as a separate embodiment, and it iscontemplated that such embodiments can be combined with each other invarious combinations or permutations. The scope of the invention shouldbe determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

1-44. (canceled)
 45. A cured film comprising a polymerization productof: a diacrylate monomer; a curing kinetics control additive; and amultifunctional crosslinking agent.
 46. The film of claim 45, whereinthe polymerization product is a polymerization product of the diacrylatemonomer; the curing kinetics control additive; the multifunctionalcrosslinking agent; and a dimethacrylate monomer.
 47. The film of claim46, wherein the concentration of the dimethacrylate monomer in thepolymerization product is less than 60 mole percent.
 48. The film ofclaim 45, wherein the concentration of the diacrylate monomer in thepolymerization product is at least 30 mole percent.
 49. The film ofclaim 45, wherein the concentration of the curing kinetics controladditive in the polymerization product is at least 0.1 mole percent. 50.The film of claim 46, wherein the polymerization product comprises: thedimethacrylate monomer at a concentration in the range from 50 molepercent to 56 mole percent; the diacrylate monomer at a concentration inthe range from 31 mole percent to 37 mole percent; the curing kineticscontrol additive at a concentration in the range from 0.2 mole percentto five mole percent; and the multifunctional crosslinking agent at aconcentration in the range from five mole percent to ten mole percent.51. The film of claim 46, wherein the dimethacrylate monomer comprises1, 12 dodecanediol dimethacrylate.
 52. The film of claim 45, wherein thediacrylate monomer comprises tricyclo[5.2.1.02,6]decanedimethanoldiacrylate.
 53. The film of claim 45, wherein the diacrylate monomercomprises decanediol diacrylate, dodecanediol diacrylate, or a mixturethereof.
 54. The film of claim 45, wherein the curing kinetics controladditive comprises a chain transfer agent.
 55. The film of claim 45,wherein the curing kinetics control additive comprises a vinyl styrenemonomer.
 56. The film of claim 55, wherein the vinyl styrene monomer isan α-methylstyrene dimer.
 57. The film of claim 45, wherein the curingkinetics control additive comprises a mono(meth)acrylate.
 58. The filmof claim 57, wherein the mono(meth)acrylate is lauryl acrylate.
 59. Thefilm of claim 45, wherein the curing kinetics control additive comprisesdodecyl thiol.
 60. The composition of claim 45, wherein themultifunctional crosslinking agent comprises a multifunctional(meth)acrylate.
 61. The film of claim 60, wherein the multifunctional(meth)acrylate is trimethylolpropane triacrylate.
 62. The film of claim45, wherein the multifunctional crosslinking agent comprises amultifunctional vinyl siloxane.
 63. The film of claim 62, wherein themultifunctional vinyl siloxane is2,4,6,8-tetramethyl-2,4,6,8-tetravinylcylcotetrasiloxane.
 64. The filmof claim 45, having a T_(g) of at least 80° C.
 65. An encapsulatedelectronic device comprising: an electronic device; and the film ofclaim 45 disposed on a substrate of the electronic device.
 66. Theelectronic device of claim 65, wherein the electronic device is anoptoelectronic device.
 67. The electronic device of claim 66, whereinthe optoelectronic device is an organic light emitting diode.
 68. Theelectronic device of claim 65, wherein the substrate is an inorganicbarrier layer.